Uterine leiomyoma is a very prevalent condition among women and, although it is mainly asymptomatic, it may be related to bothersome or debilitating symptoms, such as uterine bleeding and pelvic pain or pressure. The standard treatment is surgical (hysterectomy or myomectomy), but there has been continued interest on medical treatments. Progestagens have long been used to control bleeding associated to leiomyomas, but they have not been able to decrease myoma volume. GnRH analogs are well stablished agents, capable of controlling symptoms and decreasing the tumors´volume, but their use is limited by bone loss and menopausal symptoms. A newly introduced progestagen, dienogest, has been studied to treat endometriosis, but its effects on leiomyoma are only starting to be assessed. The investigators are aiming to compare dienogest with the GnRH analog goserelin and the progestagen desogestrel in a randomized trial to see how this new treatment compares with previously used drugs and whether it is similar, inferior or superior to them on controlling leiomyoma associated symptoms and decreasing leiomyoma volume.